In this paper，nano-aerogel thermal insulation coatings were prepared with nano-aerogel，TiO₂，SiO₂ and SiC as the fillers，alumina fiber and aluminosilicate fiber as the reinforcing material，and water-based acrylic resin as the binder. The effects of the amount ofaerogel on the dry density，thermal insulation performance and thermal conductivity of the coatings were examined. The resu-lts showed that the performance of the insulation coatings was the best when the amount of binder is 35%，the total amount of fiber added was 25%（mass ratio of alumina fiber and aluminum silicate fiber was 1∶1），and the amount of filler was 40%（mass ratio of TiO₂，SiO₂，SiC powder is 2∶1∶1 and keep the sum of the amount of aerogel to 40% of the coatings）， when the amount of aerogel is 15%，the thermal conductivity of the coatings was 0. 04 W /mK，and the dry density was 158 kg /m³. Based on the nano-aerogel thermal insulation coatings，it was studied the composite thermal insulation structure suitable for heavy oil thermal recovery steam pipe insulation. The heat-resistant fiber layer，thermal insulation coatings layer and metal shell were compounded. This composite insulation structure was successfully used in the thermal insulation renovation project of the outer layer of the heat transfer pipeline. Compared with the original thermal insulation structure，the estimated annual energy saving was equivalent to 94. 8 t standard coal，which effectively improved the thermal insulation effect of the heavy oil hot steam injection pipeline.